Book/Dissertation / PhD Thesis

FZJ-2020-02701

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Charakterisierung des Werkstoffverhaltens während des Kosinterns einer neuartigen, inert gestützten Festoxidbrennstoffzelle

Grimm, F. (Corresponding author)FZJ*

2020
Forschungszentrum Jülich GmH Zentralbibliothek, Velag Jülich
ISBN: 978-3-95806-482-9

Please use a persistent id in citations: http://hdl.handle.net/2128/25490

Abstract: Despite the advantages of solid oxide fuel cells as an potentially emission-free energy source, their commercialization has been limited due to relatively high costs that can be attributed to manufacturing and material costs. Within the KerSOLife 100 project, which is publicly funded by the Federal Ministry of Economic Affairs and Energy (BMWi), a novel all-ceramic inert-supported solid oxide fuel cell (ISC-BOSCH) was investigated. Due to the use of cost-efficient materials and a simplified manufacturing route, the total costs of the ISC-BOSCH can be drastically reduced compared to conventional cells. The ISC-BOSCH utilizes a porous manganese-silicate(forsterite), which is applied at the air side, as support material. The simplified manufacturing route is based on the sintering of all layers within one single heat treatment step, so called cosintering ,at 1200°C. In contrast, conventional solid oxide fuel cells such as the anode-supported cell (ASC) require more expensive NiO/8YSZ support materials. They are usually manufactured with three up to five heat-treatment steps which are precisely adapted to the individual layers and thus cost-intensive. However, the cost reduction of the ISC-BOSCH by using the relatively cheap support material for sterite and the simplified manufacturing route leads to a reduced cell performance. This reduced cell performance may originate from the interactions of the support material forsterite with the adjacent cathode layer during sintering and the formation of cracks and/or leakages within the electrolyte. The ISC-BOSCH uses LSM/8YSZ as cathode material, which leads to the formation of a Zn-Mn-spinel when co-sintered with forsterite, which negatively affects the cell performance. Based on these finding, two different tasks , were addressed in the present work: the adaption of the sintering properties of the 8YSZ electrolyte material to the co-sintering conditions, and the selection of a cathode which displays a high catalytic activity that is not negatively affected when co-sintered with forsterite. Concerning the 8YSZ electrolyte, the required sintering temperature of 1400°C could be reduced to 1200°C by a 5.1 mol% iron doping. To select a suitable cathode material twelve different cathodes were investigated, ranging from well-known perovskite materials such as LSC and LSF to titanates such as STO and STF and rather new Ruddlesden-Popper phases. In terms of interactions, after the co-sintering, STO showed the least interactions with forsterite. In contrast, LSF and LSC could be identified as being highly reactive with forsterite. Despite the high reaction tendency, after the co-sintering, LSF and the Ruddlesden-Popperphases displayed the lowest polarization resistances. Thus, this work demonstrates the importance of selecting a cathode material not only based on its catalytic properties, rather considering the entire manufacturing procedure of the desired cell type and precisely adjusting the layer properties to its surrounding conditions. Based on the performed impedance analyses and cell tests, the most promising cathode materials La$_{4}$Ni$_{3}$O$_{10}$, La$_{3}$Ni$_{2}$O$_{7}$ and La$_{0,58}$Sr$_{0,4}$FeO$_{3}$ are highly recommended as performance-enhancing cathode materials for the ISC-BOSCH.

Note: Dissertation, RWTH Aachen, 2020

---

Contributing Institute(s):

1. Werkstoffsynthese und Herstellungsverfahren (IEK-1)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

Appears in the scientific report 2020

---

Database coverage:
;

---